[Knatman]

I have the auto tranns and the flex plate (flywheel) cracked that felt just like a misfire i changed plugs leads coils and had a diagnostics test all made no difference then found the cracked flex plate.

If the flywheel or cluch has gone out of balance that could be your problem!!

Ian.

 

[viperhauler]

in my personal experience, an oem flywheel is the best option.

it's a solid piece of steel, from what i remember. i would check it. could be cracked - could also be a pilot bearing or the input shaft on the trans??

 

[ogromnii]

there is a small update, i took a look at flyweel from the small window between the oil pan and transmission, it's stock and solid, and has no cracks.
but the weather is dry and warm finally and we made a test drive.
this is first time i drive a monster like this and... it wasn't impressing at all. if the truck was 3.5 i would say it drives nice but... it's not what it should be. i was trying to make my own opinion without paying owner's complain attention, thinking that maybe he just wants more power but now i changed my mind, this is not the case. it runs like 150 hp honda, hardly making 130 on 6th, a bit better on 5th. owner says that the truck was accelerating nice after reaching the end of speedometer.
with tires warm after drivig is inpossible to burn them with only pressing the accelerator on 3rd, tires are old maybe original ones.
it would be nice to hear from you how your trucks behave
pilot bearing may be an issue, but not for highway lack of power i think...
as i know the only thing ever made on the car was removing original exhaust, putting something garage-made and after 2 dissapointing days refitting the original, and probably this is the point in time when problems started.
yesterday, while thinkig what could be wrong, came to idea to check if O2 sensors are positioned correctly, this is only thing (i thing) that can be wrong while reinstalling exhaust, meaning 1st bank sensor connected to 2nd or so...
also noticed gearstick kicking a little around 2500rpm at 6th and full load like cylinders missfiring, so finally it may be some issue with ECU, knowing plugs, wires and coils are new and triple checked. wire loom also checked completely, not only at 10th cylinder corner , it's made from silicone insulated wires (like in ovens) and i thing it should resist even if it fells on exhaust.
i'm out of good ideas, i see the problem, i feel it but can't figure out what's causing it. i feel comletely like accounter, not like mechanic at: shame on me :banana: :hippy:
any idea appreciated
cheers:beerchug:

 

[Crest]

Are you talking in KMH or MPH ?

Because when my truck was driving ok, my max in 6th was about 130mph (210kmh).
In 5th 160mph (255-260kmh GPS).
Did you checked if the wire loom passengre side in rear that goes to the injectors/coil are not lose and touching the headers ?
I also got some troubles with mine actually (backfire and so on) and it's a pain in the ass to debug and find the problem !

 

[viperhauler]

what about the coil packs? (they are under the intake)

are you sure the wires aren't crossed?

the best way is to remove the intake manifold... maybe the coil packs are breaking down?

that problem you just described sounds like ignition to me...

 

[ogromnii]

coil packs are new, spark wires new, for me is also looking like ignition, but except PCM everything changed with no difference. wires not crossed.
I'm talking in miles, but it looks weak to me.

 

[viperhauler]

do you have access to a dyno?

 

[ogromnii]

no, but that's idea i'll search

 

[ogromnii]

results from dyno - 425 hp at wheels

 

[mike2004srt10]

Thats exactly what mine did last summer on the Dyno.

 

[Crest]

So no problem
But misfire/backfire ?

 

[viperhauler]

results from dyno - 425 hp at wheels

what was the temperature?
what gear did you complete the dyno pull in?
did you bring the truck to redline?
is this a mustang dyno or a dynojet?

 

[ogromnii]

I wasn't there, that's what owner told me on phone
i will see him in few days and post more info
after remaping lpg injection truck made 455 on lpg but owner still complains of low torqe at 6-th, no acceleration, and gearstick shaking around 3000 rpm like engine missfiring

 

[Crest]

You should get the dynosheet, and look at the curves. If they are smooth there is no problem. The 6th is too long to get decent accelerations, mine in 6th stops around 3200RPM.
Shaky gearstick, could be he installed an aftermarket stick ? I had to recheck the bolds on the base of the stick several times, they were coming lose and made it shaking as hell !

 

[ogromnii]

i have the curves, they indicate small lack of power around 3000 rpm, i suspect missing rear cats, these days i will make some experiments

 

[SRT-10-Norway]

Hi. I have a similar problem with a SRT-10 that you had in 2014. Do you remember the solution you had?

 

[epicVIN]

Dude relax, It's ok, self-education is a vital thing even for mechanics